Automatic reclosing circuit-breaker system



Sept. 6, 1927. 1,641,724

A. E. ANDERSON AUTOMATIC RECLO'SING GIRGUI T BREAKER SYSTEM Original Filed Sept. 8, 1924 J 20\ J E Inventor:

Arvid EAndePson His Attorney.

Patented Sept. 6,1927.

UNITED STATES ARVID E. ANDERSON, OF SCOTI A, NEW

onx, AssIeNoa 'ro GENERAL ELECTRIC! COMPANY, A CORPORATION 01 NEW YORK.

AUTOMATIC BECLOSING CIRCUIT-BREAKER SYSTEM.

Application filed September a, 1924,"sena1 no. 736,447. Renewed June 1a, 1927.

My invention relates to automatic reclosing circuit breaker systems and articularly to systems in which itis desira Is to have the voltage of a circuit restored gradually 5 after the voltage has been reduced by the opening of a circuit breaker controlling the connection between a source of current and the circuit. My invention is of particular iitility in connection with automatic reclo s 1o. ing systems for circuit breakers in certain types of railway feeder circuits where it is very essential that large and sudden chan es in the trolley voltage shall not occur. or example in high voltage railway systems which supply current to trains drawn by electric locomotives a large increase in the trolley voltage may increase the pull exerted by the locomotive so quickly that the train is ulled apart.

One object of my invention is to provide an improved automatic reclosing circuit breaker system of thet p mentioned above whereby the voltage 0 the load circuit is increased gradually to its normal value after the opening of a circuit breaker due to the occurrence of a predeterminedabnormal conditionon the load circuit controlled by the circuit breaker. I

My invention will be better understood 0 from the following description. when taken in connection with the accompanying drawing andits scope will be pointed out in the appended claims. v

. Referring to the drawing, 1 and .2 represent conductors of two circuits which are adapted to be connected to other by the circuit breakers 3 and 4 whic ma be of any suitable type. As shown in'the rawing, the conductor 1 is one side of a direct current supply circuit and conductor 2 is one side.

of a direct current load circuit. It is assumed that the ground is the other side of both circuits but it is to be understood, however, that my invention is not limited to a system in which the ground is used. as one side of the system.

5 represents a current limiting resistor which is connected so that it; is short cir cuited by the circuit breaker 3, when the circuit breaker is closed, and is connected in series between the su ply anddoad circuits when the circuit brea er 4 isclosed and the circuit' breaker'3-is open-a n .1 v I It is-desirable to use a resistor which isca'- pable' of dissipating for only a short time the necessary energy consumed therein withoutbecoming excessively heated because the cost and size of such a resistor aremuch less than one which is capable of dissipating continuously the necessary energy without becoming excessively heated. Therefore, in order: that sucha resistor may be used satisfa'ctorily it is necessary to provide a suitable switching arrangement whereby the resistor'is not connected in series with the two circuits, after the circuit breaker 3 has opened inresponse to an abnormal condition on the load circuit, until it is desirable to test the condition of the load circuit. In the arrangement shown, this result is accomplished by interlocking the two circuit reakers 3 and4 so that whenever the circuit breaker 3 is opened in response to an abnormal load condition, the circuit breaker 4 is opened also to disconnect the two circuits from each other; After the circuits have remained disconnected from each other for a sufficient length of time to allow the conditions on the load circuit to become stable, a time delay relay .6, which is energized in response to the opening of the circuit breakers 3 and 4, operates and efi'ects' the closing of the circuit, breaker 4 to connect the resistor 5 in series with-the two conductors 1 and 2. While I have shown the circuit breaker 4 as being in series with the circuit breaker 3 between the two conductors 1 and 2 it is evident that, if so desired, the circuit breaker/1 ma be connected in the shunt circuit aroun the circuit breaker 4 which includes the" resistor 5.

As shown in the' drawing, the circuit breakers 3 and 4 are of the type shown and claimed in the copending application ber.v No. 511,000 filed ,Oct. 28, 1921 by John F Tritle and assighe'dto, the same assignee as this application. j l3ach circuit breaker is held in its closed position by a'holding coil 7 associated therewith and is opened when the current in a bucking bar 8, which is 1 connected so that it is energized in accordance with the current flowing in the circuit controlled by the respective circuit breaker, exceeds a predeterined value. In order that each circuit breaker may open in response to one value of loadourrent when the curparallel with each bucking bar. For clos-' mg each circuit breaker a reset coil and a resetting contactor 11 are provided therefor. The reset contactor and coil of each circuit breaker are connected and arranged so that the ener ization of the reset contactor 11 efi'ect t e energization of the reset coil 10, and the energization of the reset coil 10 moves the circuit breaker into its reset position in which position suitable auxiliary contacts are closed to effect the deenergization of the reset contactor. In the reset position of the circuit breaker the main contacts of the circuit breaker are not closed. The deener ization of the reset contactor effects the deenergization of the reset coil whereby the movable main contact of the circuit breaker is moved into engagement with the stationary main contact by a spring 12 In order that the voltage across the load circuit may be increased gradually after the circuit breaker 4 closes, the current limiting eifect of the current limiting means 5 is arranged to be varied in steps in response to the load connected to the load circuit. After the circuit breaker 4 is closed the portion 5 of the resistor 5 is arranged to. be short circuited by the contactor 14 when the voltage across the load circuit is suflicient to cause the relay 15 to close its contacts 16 which are in the circuit of the coil of the contactor 14. The voltage relay 15 has two voltage coils 17 and 18 both of which when energized tend to close the cont-act 16. The winding 17 is 'permanently connected between a point on the resistor 5 and ground so that it is energized in accordance with the voltage across the load circuit when the circuit breaker 4 is closed. The winding 18 is arranged to be connected across a suitable source of voltage by the relay 20 after the circuit breaker 4 is closed, the circuit of the coil 18 being arranged to be opened after the closing of the circuit breaker 3. 'The object in providing the relay 15 with two windings is so that the drop out value of the relay is higher than the pick up value. It will be observed that when both of the circuit breakers 3 and 4 are opened and the supply circuit is energized, substantially normal voltage remains impressed across the coil 17 since the resistance of the resistor 5 is very low compared with the resistance of the coil 17. Therefore, the relay 15 does not open its contacts 16 when the circuit breakers 3 and 4 open. When the circuit breaker 4 closes, the load, which.is connected to the load circuit, is connected in parallel with the coil 17 so that the voltage across the coil 17 decreases to a low value.

If the relay 15 had a pick up value higher than its drop out value, and the relay were adjusted so that it picked up and closed its contacts 16 when the load resistance was out value of the relay. By

age across the load circuit than the value I required to pick up the relay a better calibration is maintained so that there is no chance for a premature closing of the contacts 16. In order that the relay 15 may have suflicient time to drop out after the clos ng of the circuit breaker 4, the time delay relay 21 is provided. This relay 21 controls the circuit of the relay 20 and is designed in an suitable manner so that it does not comp etc the circuit of the relay 20 until after the circuit breaker 4 has been closed for a certain length of time.

After the portion 5 of the resistor 5 has been short circuited by the contactor 14, the portion 5 is short circuited by means of a contactor 23, when the current through the portion of the resistor 5, which is not short circuited, decreases below a predetermined value. The circuit of the coil of the contactor 23 is controlled by a relay 24 having a winding 25 connected in parallel with the resistor 5 so that (it is energized in accordance with the current flowing through the resistor from the sup ly circuit to the load circuit. Since the relay 24 is arranged to operate when the current decreases below a predetermined value and the coil 25 is short circuited under normal operatingxconditions it is necessary to provide suitable means for causing the relay' 25 to open its contacts 26 when the circuit breaker 3 opens and to maintain its contacts 26 open independently of the current through the coil 25 until after the contactor 14 has short circuited the portion 5 of the resistor 5. In order to accomplish this result the relay 24 is provided with a Winding 27, the circuit of which is completed by a relay 28 as soon as the circuit breaker 3 opens. The winding 27 is arranged so that when it is energized, it opens the contacts 26 and maintains the contacts open independently of the amount of current through the coil 25 The circuit of the coil 27 is also controlled by the contactor 14 so that as soon as the portion 5 of the resistor 5 has been short circuited the coil 27 is deenergized and the relay 24 is 'free to operate in response to the current through the resistor 5 to effect the, closing of the coil circuit of the contactor 23- After the portion 5 of the resistor 5 has been short circuited, the circuit breaker 3 is arranged to be closed when the current through the portion of, the resistor 5, remaining connected in series between the conductors 1 and 2, decreases below a predetermined value.' This result is accomplished by means of a relay 30, the contacts 31 of which are connected in the circuit of the coil of the reset contactor- 11 of the circuit breaker 3. The relay 30 is provided with a a. winding 32 which is connected in parallel with the resistor so that it is energized in accordance with the current flowing through the resistor from the supply circuit to the load circuit, and with a winding 33, the cir- 0 cuit of which is completed by the relay 28 as soon as the circuit. breaker 3 opens so that the relay opens its contacts 31 and maintains them open until after the contactor 23 closes. When the contactor 23 closes, the

15 circuit of the coil 33 is opened so that the it is evident that the number of steps in which the resistor 5 is short circuited ma be made any'de sired number. by merely ad mg adclltional relays similar to relay 33 and additional contactors similar to contactor 23, and havlng them interlocked in the manner shown so that they will operate in a predetermined sequence.

In order to protect the resistor 5 in case the temperature thereof becomes excessive,

"* suitable temperature responsive devices such as thermostats are placed near or on different portions of the resistor 5. These thermostats control the "circuit of the relay 28 so that in case the temperature of any portion of the resistor becomes excessive, the

relay 28 is deenergized and in a manner hereinafter described effects the opening of the circuit breaker 4 and renders ,the reclosing equipment inoperative until the overheated portion of the resistor 5 has cooled.

a The operation of the system shown is as follows: When the load conditionsare normal and both of the circuit breakers 3 and I 4 are closed, these circuit breakers are held 59 in their closed positions by their respective holding coils 7;. The circuit of the holding coil 7 of the circuit breaker 3 is from one side of a suitable sdurce of current shown as a battery 39 through conductor 40, con-.

55 tacts 412m the circuit breaker 4, conductor 42, holding coil 7 of the circuit breaker 3,. conductor 43, resistor 44 to the ground which 7 is connected to'the other side of the battery.

While 'I have shown the control circuit, supplied by the battery 39, as having one side grounded in order to simplify the drawing, 1t may be preferable in practice tousean ungr'ounded system. The circuit 0f "the 40, contacts on the circuit breaker 3, conductor 46, holding. coil 7 of circuit breaker 4, conductor 47, resistor 48 to ground. It will be observed that the circuit of each holding coil 7'is controlled by contacts on the other circuit breaker so that if one circuit breaker is opened, the other one is opened also.

,When both of the circuit breakers 3 and 4 are closed, the ,other control devices are in the positions shown in the drawing. The contacts 16 of the relay 15 are closed since substantially normal voltage. is impressed on the winding 17 -thereof.

Upon the occurrence of a predetermined abnormal load condition thecurrent through the bucking bar of one of the circuit breakers, depending upon the adjustments there.- of, causes in a, well known manner, the opening of the circuit breaker and the opening of this circuit breaker causes the opening of the otherin the manner above described.

'When the circuit breaker 3 opens the closin of its auxiliary contacts 49 complete acircuit from the battery 39 through the conductor 40, contacts 49, conductor 50, thermostats 35, coil of relay 28 to ground. The closing of the contacts 51 of the relay 28,

when it is energized, connects the coils 27 and 33 of the relay 24 and 30 respectively across the battery 39 so'that both of these relays open their respective contacts 26 and i 31. The closing of the contacts 52, when rela 28 is energized, completes the circuit of t e time delay'relay 6 and the holding coil 7 of circuit breaker 4. This circuit is from the battery 39, through conductor 40, contacts 52, and conductor 46 which isco'nnected to ground through two branches.

One branch includes the holding coil 7 of the circuit breaker 4, conductor 47 and resistor 48 and the other branch includes the 'for the reset contactor 11 of the circuit breaker 4. This circuit includes the coil of the reset contactor 11, conductor 56, contacts of-the time delay relay 6, conductor 57, contacts 58 of the contactor 14, conductor 59;..cont'a cts 60 on the circuit breaker 3 to ground. The completion of this circuit in parallel with thefresistor 48 increases the current throughthe holding coil 7 which is desirable" during the closing period. The

the reset con contacts 53 on the circuit breaker 4, conduc from the battery 39 through the conductor 1 holding coil 7 of the circuit breaker '4 is closing /of the contacts 61 of tactornll connects the reset ccil 10 of the circuit breaker 4 across the battery 39 so that the circuit breaker 4 is moved into its reset position in which position the main contacts of the circuit breaker are not closed but the auxiliary contacts 53 are open and the auxiliary contacts 41, 62 and 63 are closed The closing of the contacts 63 completes a short circuit around both the resistor 48 and the coil of the reset contactor 11 so that the energization of the holding coil 7 is further increased. The short circuiting of the reset contactor 11 causes this device to open its contacts 61, thereby efl'ecting the deenergization of the reset coil 10, whereupon the spring 12 closes the main contacts of the circuit breaker 4 so that the resistor 5 is connected in series between the .two conductors 1 and 2.

The opening of the auxiliary contacts 53 opens the circuit of the time delay relay 6 which returns to its normal position. The closing. of the' auxiliary contacts 41 completes the heretofore described circuit of the holding coil 7 of the circuit breaker 3. The closing of the auxiliary contacts 62 completes a circuit for the time delay relay 21 from the battery 39, through conductor 40 auxiliary contacts 49 on the circuit breaker 3, conductor 50, auxiliary contacts 62 on the circuit breaker 4,1conductor 65, coilof time delay relay 21, to ground.

With a short circuit or an overload abovea predetermined value connected across the load circuit, the voltage across the winding 17 decreases to'such a low value, when the circuit breaker 4 closes. that the relay 15 opens its contacts 16. Therefore, when-the relay 2O closes its contacts after the circuit breaker 4 has been closed a certain length of time,,the circuit of 'the contactor'14 is not completed to short circuit. the portion 5 of the resistor until the voltage across the load circuit has increased to a predetermined value thereby indicating that the load has decreased below a predetermined value.

After a predetermined time, the time relay 21 closes its contacts 64 and completes a circuit in parallel with the coil thereof. This circuit extends from the conductor 65 through the contacts 64 of the relay 21, conductor 65, coil'of relay 20 to ground. The

closing'of the contacts 66 of the relay 20 connects the coil. 18 of the voltage relay 15 across the battery 39. Theenergization of the coil 18 alone 1s not sufficient to cause the relay15 to close its contacts. 16 but partially energizes the relay so that the relay operates in response to a lower voltage across the load circuit than if only the winding 17 were used.

As soon as the voltage across the load cir- "cuit reaches a, predetermined value, after the operation of the relay 20, the relay 15 closes its contacts 16 and completes a circuit for the coil of the contactor 14 to short tactor completes a locking circuit for itself.

The opening of the contacts 58 removes the short circult from aroundthe resistor 48 so that the energization of the holding coil 7 is reduced to its normal value; The open ing of the contacts 70 eifects the deenergization of the coil 27 of the relay 24 so that the relay is free to close its contacts 26 in response to the current flowing through the portion of the resistor which is not short circuited. Q

As soon as the load conditions become such, after the operation of the contactor 14, that the current through the resistor 5 permits' the relay 24 to close its contacts 26, a circuit is completed for the coil of the contactor 23 so that the portion 5". of the resistor 5 is short circuited. The circuit is from the battery 39, through the conductor 40, contacts 66 of the relay 20, conductor 67. contacts 26 of the relay 24, conductor 71, coil of contactor 23 to ground. The closing of the contacts 72 of the contactor 23 also connects together the conductors 67 and 71 so that the contactor 23 completes a locking circuit for itself. The opening of the contacts 73 of the contactor 23opens the circuit of the coil 33 of the relay 30' so that the relay 30 is freetoclose its contacts 31 in response to the current flowing through the portion of the resistor 5 which is not short circuited.

As soon as the load conditions become such, after the operation of the contactor 23, that the current through the resistor permits the relay 33 to close its contacts 31, a circuit is completed in parallel withthe resistor 44 for the reset contactor 11 of the circuit breaker 3. This parallel circuit extends from the conductor 43, through the coil of the reset contactor 11, conductor 74, contacts. 31 of the relay 30, conductor 75, contacts 76 of the contactor 23to ground. Since this circuit is in parallel with the re sistor 44, the energization 'of the holding coil 7 of the circuit breaker 3 is increased during the resetting operation thereof. The closing of the contacts 77 of the reset contactor 11 connects the reset coil 10 of the circuit breaker 3 across the battery 39 so that the circuit breaker 3 is moved into its reset position, in which position the main contacts of the circuit breaker are not closed, but the auxiliary contacts 49 and 60 are open and the auxiliary contacts 45 and 78 are closed.

The closing of the auxiliary contacts 45 malaise completes a circuit around the contacts 52 of the relay 28 so that the circuit of the p in addition to effecting the deenergization of the relay 28, also effects the deenergization In breaker system, a supply circuit a load cirof the time relay 21 and the relay 20. order to prevent the contacts 66 of the relay 20 from being opened, until ,after the closing operation of the circuit breaker 3 has been completed, any suitable means such as a dashpot may be provided for accomplishing this result.

The closing of the auxiliary contacts 78 connects the conductor 43 directly to ground through conductor and contacts 76 of the contactor 23 so that the reset contactor 11 and the resistor 44 are short circuited and the excitation of the holding coil 7 of the circuit breaker is increased during the closing of the main contacts of the circuit breaker. The opening of the contacts 77 of the reset contactor ll of the circuit breaker 3 deenergizes the reset coil 10 thereof so that the main contacts of the circuit breaker 3 are closed to connect the conductors 1 and 2 directly together.

When the relay 20 opens its contacts 66 after the closing of the circuit breaker 3, the contactors 14 and 23 open. The opening of the contacts 76 of the contactor 23 removes the short circuit around the resistor 44 so that the energization of the holding) coil 7 of the circuit breaker is decreased ut not enough to cause the circuit breaker 3 to open. In case the temperature of any portion of the resistor 5 becomes excessive after the circuit breaker 4 closes, and before the resistor is short circuited by the circuit breaker 3,

the circuit of the relay 28 is opened b one or more of the thermostats 35 associate with the resistor. The opening of the contacts 52 of the relay 28 opens the circuits of the time delay relay 6 and the holdin coil 7 of the circuit breaker 4 so that tfii's circuit breaker opens. The opening of t 's circuit breaker efi'ects the opening of the coil circuits of the relays 21 and 20 and the contactors L4 and 23. The opening of the contacts 51 of the relay 28 o ens the circuits of the coils 27 and 33 of t e relays 24 and 30, respectively. Consequently, all of the control devices for the two circuit breakers are restored to their normal position so that neither of the circuit breakers can be reclosed automatically until the resistor has across said load cooled and the circuit of the relay '28 is comleted.

While I have, in accordance with the provision of the patent statutes, shown and described my invention as applied to'a particular system and as embodying various devices diagrammatically indicated, changes and modifications will be obvious to those skilled in the art, and I, therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the .United States is 1. In an automatic reclosing circuit rent limiting efl'ect of said current limiting means whenthe load is less than a predetermined value after the opening of said circuit breaker, and means controlled by the currentsupplied through said current lim- "iting means and operative only after the o ration of said load responsive means for e eating the closing of said circuit breaker.

2. In an automatic reclosing circuit breaker system, a supply circuit a load circuit, a circuit breaker arranged to connect said circuitsrtogethe'r, current limiting means arranged to be connected in series w1th said circuits when said circuit breaker is o ned and to be short circuited by said circuit breaker when it is closed, means for opening said circuit breaker in res onse to a redetermined abnormal condition on sai load circuit, means responsive to the voltage across said load circuit for decreasing t e current limiting'efiect of said current limiting means, and means responsive to the current flowing between said circuits through said current limiting means :for subsequentl effecting the closing of said circuit brea er.

3. In an automatic reclosing circuit breakersystem, .a supply circuit, a loadcircuit, a circuit breaker arranged to connect said circuits together, current limiting means arranged to be connected in series with said circuits when said circuit breaker is opened and to be circuit breaker when it is closed, means for opening said circuit breaker in response to a predetermined abnormal condition on said load circuit, means responsive to the voltage circuit for short circuiting a portion of said current limiting means, and current responsive means operatlve subsequent to the operation of said voltage responsive short circuiting means to short circuit another portion of said current limiting means and to effect the closing of said circuit breaker in ,a predetermined sequence.

4. In an automatic reclosing circuit breaker system, a supply circuit, a load circuit, a circuit breaker arranged to connect said circuits directly together, current limiting means, means for opening said circuit breaker in response to a predetermined abnormal condition on said load circuit, means operative after said circuit breaker has been open for a predetermined length of time for connecting said current limiting means in series between said'circuits, means operative to short circuit a-pprtion of said current limiting means when the load is less than a predetermined value after said current limiting means has been connected in series between said circuits for a predetermined length of time; and means controlled by the current through said current limiting means for short clrcuiting another portion of said current limiting means and for effecting the closin of said circuit breaker in a predetermine sequence after said load ressonslve short circuiting means has operate 5. In an automatic reclosing circuit breaker system, a supply circuit, a load circuit, current limiting .means, a circuit breaker adapted to connect said current limiting means in series between said circuits, a second circuit breaker adapted to short circuit said current limiting means,means for opening said second circuit breaker upon the occur: rence of a predetermined abnormal condition of saidload circuit, means responsive to the opening of said second circuit breaker for effecting the closing of said first-mentioned circuit breaker, means operative in response to the Voltage across said load circuit for short circuiting a portion of said current limiting means after the closing of said first mentioned circuit breaker, means controlled by the current through said current limiting means ,for short circuiting another portion of said current limiting means after the operation of said voltage responsive short circuiting means, and means controlled by the current through said current limiting means for effecting the closing of said second circuit breaker after said other portion of said current limiting means has been short circuited.

6. In combination, a supply circuit, a load circuit, a circuit breaker adapted to connect said circuits together, current limiting means arranged to be-connected in series with said circuits when said circuit breaker is opened, means for short circuiting a portion of said current limiting means comprising an electroresponsive means having one winding connected across said load circuit and another winding arranged to be energized after said circuit breaker opens, and means for short circuiting another portion of said current limiting means comprising an electrorespon-, sive device having a winding arranged to be energized in response to the opening of said circuit breaker to move said electroresponsive device to its energized position and to be deenergized in response to the operation of said voltage responsive short circuiting means and a winding connected so as to be responsive to the current through said current limiting means. I

7. In combination, a supply circuit, a load circuit connected to said supply circuit, means operative in response to a predetermined abnormal condition on said load circuit forefitecting the disconnection of said load circuit from said supply circuit, a current limiting resistor, switching means for connecting said current limiting resistor in series with said circuits after said circuits have been disconnected from each other for a predetermined length of-time, and means for short circuiting said resistor comprising a relay having a winding permanently connected to said supply clrcuit with said resistor in series therewith, and a second winding arranged to be energized after said resistor has been connected in series with said circuit for a predetermined length of time.

8. In combination, asu 1y circuit, a load circuit connected to said supply circuit, means operative in res onse to a predetermined abnormal conditlon on said load circuit for effecting the disconnection of said load circuit from said supply circuit, current limiting means, switching means for connectlng said current limiting means 1n serles with said c1rcu1ts after said c1rcu1ts have been disconnected from each other, and

means for decreasing the current limiting effect of sald current l1m1t1ng means comprising a relay having a winding arranged to be connected across'said load circuit by said switching means, and a second winding arranged to be energized after said switching means has been operated to connect said circuits together.

9. In combination, two electric circuits, current limiting means arranged to be connected in series with said circuits, and means for decreasing the current limiting effect of said current limiting means comprising a relay having a winding connected so as to be responsive to the current through said current limiting means and a second winding arranged to be energized until a predtermined condition occurs on one of said circuits after said current limiting means is connected in series with said circuits to prevent saidrela from effecting the short circuiting of sai current limiting means.

10. In combination, two electric circuits, a circuit breaker for connecting said circuits together, current limiting means arranged to be connected in series with said circuits in response to the opening of said circuit breaker, and recloslng means for said circuit breaker comprising a relay having a winding connected so as to be responsive to the current through said current limiting means, and a second winding arranged to be energized in response to the opening of said circuit breaker and before said current limiting means is connected in series with said circuits to prevent said relay from effecting the operation of said reclosing means, and to be deenergized in response .to a predetermined condition on one of said circuits after said current limiting means has been connected in series with saidcircuits.

11. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker -for connecting said circuits together, current limiting means, means operative in response to an abnormal condition on one of said circuits for eilecting the opening of said circuit breaker, means operative after said circuit breaker has been open for a predetermined length of time for connecting said current limiting means in series with said circuits, and means for controlling the reclosing of said circuit breaker comprising a relay having a winding arranged to be energized upon the opening of said circuitbreaker andto be deenergized after said current limiting means has been connected in series with said circuits and a second winding connected so as to be responsive to the current through said current limiting means.

12. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, circuit limiting means arranged to be connected in series with said circuits when said circuit breaker is openedfand means for decreasing the current limiting elfect of said current limiting means comprising a relay having a winding arranged to be energized in response to the opening of said circuit breaker and to be deenergized after said current limiting means has been connected in series with said circuits, and a second winding-connected so as to be responsive to the current through said current limiting means.

13. In combination, two electric circuits, a circuit breaker for connecting said circuits together, current limiting .means arranged to be connected in series with said circuit in response to the openin of said circuit breaker, and meansfor ecreasing the current limiting effect of said current limiting means comprising a relay having a 1 winding connected so as to be responsive to the current through said current limiting means and a second winding arranged to be means arranged to be connected in series with said circuits when said circuit breaker is opened, means operative in response to the voltage across said load circuit for short circuiting a portion of said current limiting means, and a relay for eflecting the short circuiting of another portion of said current limiting means comprising a winding connected so as to be responsive to the current supplied from said supply circuit to said load circuit through said current limiting means and a second winding arranged to be energized in response to the opening of said circuit breaker to prevent said relay from eflecting the short circuiting of said other portion of said current limiting means and to be deenergized in response to the operation of said voltage responsive short circuiting means to permit said relay to effect the short circuiting of said other portion of said current limiting means when the current through itis below a predetermined value. v

15. In combination, a supply circuit, a load circuit, a circuit breaker for connecting, said circuits together,,current'limiting means arranged to be connected in series with said circuits when said circuit breaker is opened, means operative in response to the voltage across said load circuit for decreasing the current limiting eflect of said current limiting means, and reclosing means for said circuit breaker comprising a, relay having a winding connected so as to be responsive to the current supplied to said load' circuit by said supply circuit through said current limiting means, and a second winding arranged to be energized when said circuit breaker opens to prevent'said relay from effecting the operation of said reclosing means and to be deenergized after the operation of said voltage responsive short circuiting means to permit said relay to effect the operation of said reclosing means when the current through said current limiting means is below a predetermined value.

16. In combinatio a supply circuit, a load circuit, a circuit breaker for connecting said circuits together, current limiting I means arranged to be connected in series with said circuits when said circuit breaker is opened, means operatlve 1n response to the current through said current limiting means for decreasing the current limiting effect thereof, and reclosing means for said circuit breaker comprising a relay having a Winding connected so as to be responsive to the current supplied to said load circuit by said supply circuit through said current v limiting means and a second winding arranged to be energized when sald circuit 1 breaker opens to prevent said relay from my hand.

ARVID E. ANDERSON. 

